A native of Alexandria. During the persecutions of the Christians he hid himself and fled to Scio, lodging with a woman and her three daughters, women of evil life, but whom he succeeded in converting. And a demon was there inhabiting an Ethiopian, and when he saw Isidore he prayed that the saint would not cast him into the abyss. Isidore promised the demon this favour, if he would slay a dragon which tenanted a well in the island and killed many. The demon accepted this condition, and by his means the people were freed from a terrible scourge. But when the praetor Numerianus heard of it, he took Isidore and, after beating him with ox thongs, he cast him into prison. The following day, as he would not renounce Christ, he was bound to a horse and dragged over rough ground, but by the grace that was in him the briars and thorns there were transformed into beautiful and fragrant trees. Then he was put into the fire, but on coming out uninjured he was beheaded. His body was taken away and buried by a holy matron. But in the time of the Doge Michael of Venice the body came into the possession of the Venetians, who carried it to their city, where it rests in the basilica of San Marco. 15th May.